温度对水泥乳化沥青砂浆韧性的影响

Influence of Temperature on Toughness of Emulsified Asphalt Cement Mortar

采用三点弯曲法测试了不同温度下水泥乳化沥青砂浆的荷载一挠度曲线，通过对荷载一挠度曲线面积的积分得到了水泥乳化沥青砂浆的断裂能，进而获得了温度对水泥乳化沥青砂浆韧性的影响规律；采用扫描电子显微镜观察了水泥乳化沥青砂浆的微观形貌，探讨了温度对水泥乳化沥青砂浆韧性的影响机理．结果表明：在-40～80℃下，随着温度的升高，受弯水泥乳化沥青砂浆出现由脆性断裂至韧性断裂再到柔性断裂的逐次转变．当沥灰比（质量比）为0．30时，水泥乳化沥青砂浆韧性随温度的变化不大；当沥灰比为0．45～0．90时，水泥乳化沥青砂浆韧性随温度的增加先增加后降低，在-10℃左右时砂浆韧性最好．随着沥灰比的增加，水泥乳化沥青砂浆韧性对温度的敏感性逐渐增大．当沥灰比逐渐增加时，水泥乳化沥青砂浆中的沥青形成连续膜；随着沥灰比的继续增加，砂浆中沥青膜厚度增加，从而导致砂浆韧性对温度的敏感性逐渐增强．

The load-deflection curves of emulsified asphalt cement mortar were tested by three-point ben- ding test at different temperatures, and the fracture energy was obtained by integrating the area under the load-deflection curve. The effect of temperature on the toughness of emulsified asphalt cement mortar was revealed. The microstructure of emulsified asphalt cement mortar was observed by scanning electron mi- croscopy（SEM）. The results indicate that, with the increase of temperature from --40 ~C to 80 ~C, the fracture modes of emulsified asphalt cement mortar in bending transform from brittle fracture to ductile fracture, finally to flexible fracture. When the ratio（by mass） of asphalt to cement is 0.30, the toughness of emulsified asphalt cement mortar shows little change as the temperature variation. When the ratio of as phalt to cement ranges from 0.45 to 0.90, the toughness of emulsified asphalt cement mortar increases at first and then decreases gradually with the increase of the temperature, and reaches the maximum value at about --10 ~C. It is concluded that the higher the ratio of asphalt to cement, the greater the temperature sensitivity of the toughness. When the ratio of asphalt to cement increases, the continuous film of asphalt in the emulsified asphalt cement mortar appear, and with the ratio of asphalt to cement continued increas- ing, the thickness of the asphalt film raises, which leads to the increase of the temperature sensitivity of the toughness.